Method and apparatus for creating a working opening through an incision

ABSTRACT

In accordance with the present invention, there is disclosed surgical methods and apparatus for accessing and stabilizing the heart. The methods and apparatus facilitate access to an anastomosis site, allows various instruments or devices to be maneuvered and secured in place, and provide stabilization of the heart. In particular, the apparatus involves a retractor assembly having a pair of opposing blades having a channel adapted to engage an incision in a patient. The retractor blades may have features to cooperatively engage an instrument mount. The instrument mount may hold an instrument, such as a tissue stabilizer, and allows the instrument to be easily maneuvered. The retractor blades may have a number of suture locks for securing sutures used during surgery. The retractor system is particularly useful in accessing, positioning and stabilizing the beating heart for coronary artery bypass graft surgery.

FIELD OF THE INVENTION

The present invention relates generally to surgical instruments, andmore particularly to surgical retractor, instrument mount, and tissuestabilizer devices for use during coronary artery bypass graft surgery.

BACKGROUND OF THE INVENTION

Diseases of the cardiovascular system affect millions of people eachyear and are a leading cause of death throughout the world. The cost tosociety from such diseases is enormous both in terms of the number oflives lost as well as in terms of the costs associated with treatingpatients through traditional surgical techniques. A particularlyprevalent form of cardiovascular disease is a reduction in the bloodsupply leading to the heart caused by atherosclerosis or other conditionthat creates a restriction in blood flow at a critical point in thecardiovascular system that supplies blood to the heart.

Treatment of such a blockage or restriction in the blood flow leading tothe heart is, in many cases, treated by a surgical procedure known as acoronary artery bypass graft (CABG) procedure, more commonly known as a“heart bypass” operation. In the CABG procedure, the surgeon “bypasses”the obstruction to restore normal blood flow to the heart either byattaching an available source vessel to the obstructed target coronaryartery or by removing a portion of a vein or artery from another part ofthe body, to use as a graft, and installing the graft between a point ona source vessel and a point on a target artery.

To restore the flow of blood to the heart, the CABG procedure requiresthat a fluid connection be established between two vessels. Thisprocedure is known as an “anastomosis.” Typically, a source vessel, suchas a source artery with an unobstructed blood flow, i.e., the leftinternal mammary artery (LIMA), or a bypass-graft having one end sewn toan unobstructed blood source such as the aorta, is sewn to a targetoccluded coronary artery, such as the left anterior descending (LAD)artery or other vessel, that provides blood flow to the muscles of theheart.

Although the CABG procedure has become relatively common, the procedureitself is lengthy and traumatic and can damage the heart, thecardiovascular system, the central nervous system, and the blood supplyitself. In a conventional CABG procedure, the surgeon makes an incisiondown the center of the chest, cuts through the sternum, performs severalother procedures necessary to attach the patient to a heart-lung bypassmachine, cuts off the blood flow to the heart, and then stops the heartfrom beating in order to complete the bypass. The most lengthy andtraumatic surgical procedures are necessary, in part, to connect thepatient to a cardiopulmonary bypass (CPB) machine to continue thecirculation of oxygenated blood to the rest of the body while the bypassis completed.

In recent years, a growing number of surgeons have begun performing CABGprocedures using surgical techniques especially developed so that theCABG procedure could be performed while the heart is still beating. Insuch procedures, there is no need for any form of cardiopulmonarybypass, no need to perform the extensive surgical procedures necessaryto connect the patient to a cardiopulmonary bypass machine, and no needto stop the heart. As a result, these beating heart procedures are muchless invasive and the entire procedure can typically be achieved througha small number, typically one or two, comparatively small incisions inthe chest.

Despite the advantages, the beating-heart CABG procedure is notuniversally practiced, at least in part, because of the difficulty inperforming the necessary surgical procedures using conventional surgicalinstruments. For example, it has been difficult for the surgeon toaccess the required areas of the heart requiring revascularization. Inaddition, the various surgical steps that are required to be performedon the heart itself are more difficult to perform because the heartmuscle continues to move and contract to pump blood throughout theduration of the procedure.

The specific portion of the surgical procedure that creates theanastomosis in the beating-heart CABG procedure is particularlydifficult. Completion of the anastomosis requires placing a series ofsutures through extremely small vessels on the surface of the heartwhile the heart muscle continues to beat. Moreover, the sutures must becarefully placed to ensure that the source vessel or graft is firmlyattached and will not leak when blood flow through the vessel isestablished. In cases where the target coronary artery is temporarilyobstructed, for example, to improve the surgeon's visibility and avoidexcessive blood loss, it is also important that the anastomosisprocedure be performed rapidly to avoid ischemic damage to the heart.

Further adding to the difficulty of the procedure is the fact that theworking space and visual access are often quite limited. The surgeon maybe working through a small incision in the chest, for example, or may beviewing the procedure on a video monitor if the site of the surgery isviewed via surgical scope. The vessel, and particularly the arteriotomyto which a source vessel is to be anastomosed, may also be verydifficult for the surgeon to see as it may be obscured more or less bylayers of fat or other tissue.

The beating-heart CABG procedure could be greatly improved if the heartcould be accessed and stabilized during the procedure such that themotion of the heart, particularly at the site of the anastomosis, isminimized even though the heart continues to beat and supply blood tothe body. The beating-heart CABG procedure could be further improved ifthe target vessel, and specifically the arteriotomy was presented to thesurgeon in a way that allows sutures to be easily placed.

In view of the foregoing, it would be desirable to have improved devicesfor accessing and effectively stabilizing the beating heart at the siteof the anastomosis. It would be desirable to have a retractor systemthat provides unobstructed and organized access to the areas of theheart requiring revascularization. It would be further desirable to havea low-profile, atraumatic stabilizing device that stabilizes the beatingheart at the site of the anastomosis and provides a favorablepresentation of the target vessel and the arteriotomy. It would befurther desirable to provide a mount for the stabilizing device, orother instruments, that allows the stabilizing device to be easilymaneuvered to the desired position and orientation, fixedly secureduntil the procedure is completed, and then easily removed from the siteof the anastomosis.

SUMMARY OF THE INVENTION

The present invention will be described for use in performing CABGsurgery, but the invention is not limited thereto, and is contemplatedto be useful for other surgical procedures requiring access through anincision into a patient.

The present invention involves various aspects of a surgical retractorfor use, for example, in performing a CABG procedure on a beating heart.The present invention may involve a surgical retractor which facilitatesthe creation of a working opening through an incision in a patient, suchas a sternotomy. The surgical retractor may also provide a platform forsecurely mounting various instruments or for organizing such things assutures. The present invention may also include an instrument mountwhich may be secured to the platform.

One aspect of the present invention involves a surgical retractor systemfor creating an opening through an incision in a patient which includesa drive mechanism and one or more retractor blades detachably mounted tothe drive mechanism. The drive mechanism may have a first housing and asecond housing, the first housing being moveable relative to the secondhousing. In a preferred embodiment, the housings are associated with atoothed bar which provides a means for driving one housing relative tothe other.

The surgical retractor system preferably has first and second retractorblades each having a first end, a second end, and a retractor bodyextending therebetween. The first ends of the first and second retractorblades are preferably detachably mounted, coupled, or otherwise attachedto the first and second housings, respectively. The first and secondretractor blades preferably have at least one channel adapted to receiveopposite sides of the incision. Preferably, the channel or channels areadapted to receive opposite sides of a severed or incised sternum.

The surgical retractor system may also include an elongate rail orientedalong at least a portion of a length of at least one of the retractorbodies. Preferably, each retractor blade has a rail that extendssubstantially from end to end of the length of the retractor. The railmay be a channel formed within the retractor body or may extendoutwardly from the retractor body. The rail may be substantiallystraight along its length or may be curved along its length.

Preferably, the rail extends outwardly from the retractor body and has atop section adapted to engage a separate mount. In one embodiment, therail has a top portion and a bottom portion, the bottom portion having anarrowed region adjacent the top portion and forming first and secondtabs on the top portion. Most preferably, the rail has a T-shapedcross-section.

The surgical retractor system may further comprise a plurality of sutureholders, preferably associated with the rail. The rail may include aplurality of open slots, transverse to said rail, for receiving one ormore sutures. The open slots may include a means for locking the sutureswithin the open slots. In one embodiment, the open slots have a firstslot section which bifurcate into a second slot section and a third slotsection. Each of the second and third slot sections may have a means forlocking sutures within the second and third slots respectively. In apreferred embodiment, open slots have a depth that allows the sutures tobe positioned below the top section of the rail.

The surgical retractor system may also provide features that allow theretractor blades to be securely mounted to the drive mechanism. Thefirst and second housings may have at least one pin extending therefromand each of the first and second retractor blades have a mating holeformed therein for receiving the pins when the first and secondretractor blades are attached to the first and second housings.Preferably, the pins may be cylindrical or tapered.

The present invention may also involve a surgical retractor system forcreating an opening through an incision in a patient which includes adrive mechanism having a first retractor blade and a second retractorblade attached thereto. The blades are preferably substantially parallelto each other and adapted to engage opposite sides of the incision.Preferably, the blades being moveable relative to one another. At leastone of the blades has a rail extending upwardly from it with at leastone open slots for receiving one or more sutures therein. The rail mayhave a top section adapted to engage a separate mount. Preferably, therail has a T-shaped cross-section and may be curved or straight alongits length.

The surgical retractor system may have at least one open slot transverseto the rail, the open slot having a depth which allows one or moresutures to be positioned completely below the top section. Preferablythe open slot has an internal wall and the surgical retractor systemfurther comprises a suture locking member. The suture locking memberincludes a body having a fixed end and a free end, the free end engagingthe internal wall so as to clamp a suture placed between the free endand the internal wall. The body may be flexible or substantially rigidand pivotable about the fixed end. The body may be at an acute anglerelative to the open slot.

In another aspect, the present invention involves a surgical retractorfor use in operating on a heart and includes a drive mechanism havingone or more retractor blades having an open suture channel or slothaving a pivoting suture lock. In one embodiment the surgical retractorincludes a drive mechanism having a first retractor blade and a secondretractor blade in an opposing relationship for engaging opposite sidesof an incision made within the thoracic cavity. The first retractorblade is typically moveable relative to the second retractor blade tocreate a widened opening through the incision. At least one of theretractor blades preferably has an open slot for receiving a suture.

The surgical retractor preferably has a suture locking member having abody with a fixed end and a free end, the body being pivotable about thefixed end so as to urge the free end against an internal wall of theopen slot. The body generally has a central axis extending from the freeend to the fixed end, the central axis of the body being at an angle ofless than 90 degrees with the open slot. More preferably, the body is atan angle of more than about 65 degrees and less than about 90 degrees.In a preferred embodiment, the free end has a number of ridges formedtherein. Preferably, at least a potion of the fixed end is substantiallycylindrical and the surgical retractor may include a mating cylindricalcavity or recess.

These and other features of the present invention will become more fullyapparent from the following description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a cardiac surgery systemaccording to the principles of the present invention.

FIG. 2 is a perspective view illustrating a retractor assembly accordingto the principles of the present invention.

FIG. 3 is a perspective view illustrating a preferred retractor driveassembly.

FIG. 4 is a perspective view illustrating an exemplar bar assembly.

FIG. 5 is a perspective view illustrating a moveable housing associatedwith the retractor drive.

FIG. 6 is a perspective view illustrating a retractor drive handleassembly.

FIG. 7 is a top plan view illustrating a preferred platform blade andretractor drive assembly in an unengaged position.

FIG. 8 is a top view in partial cross-section illustrating the platformblade and retractor drive assembly in an engaged position.

FIG. 9 is a cross-sectional view taken along line 9—9 shown in FIG. 8.

FIG. 10 is a partial top view illustrating a preferred suture stayarrangement associated with a platform blade.

FIGS. 11A, 11B, and 11C illustrate a preferred platform blade latch.FIG. 11A and 11B are top and front plan view, respectively. FIG. 11C isa cross-sectional view taken along line 11C—11C as shown in FIG. 11B.

FIG. 12 is a perspective view showing a preferred suture lock.

FIG. 13 is a perspective view illustrating an instrument mount assemblyaccording to the principles of the present invention.

FIG. 14 is an exploded assembly illustration of the instrument mountassembly of FIG. 13.

FIGS. 15A and 15B are perspective views illustrating the assembly of themount cam to the mount base.

FIGS. 16A and 16B are top and front plan views, respectively,illustrating a preferred mount cam.

FIG. 17 is a front plan view illustrating a preferred mount hinge.

FIG. 18 is an exploded view illustrating the assembly of the mount bodyto the mount base.

FIG. 19 is an exploded view illustrating the assembly of the instrumentclamp to the mount body.

FIG. 20 is a cross-sectional view taken through a horizontal plane ofthe instrument shaft grip of FIG. 19.

FIG. 21 is a front plan view showing an assembled instrument mountoperably positioned on a platform blade according to the principles ofthe present invention.

FIGS. 22A and 22B are front and top plan views, respectively, of analternate instrument mount assembly according to the principles of thepresent invention.

FIG. 23 is a cross-sectional view taken along line 23—23 as shown inFIG. 21.

FIG. 24 is an offset cross-sectional view taken along line 24—24 asshown in FIG. 22 illustrating the mount assembly of FIGS. 21 and 22 inthe closed position.

FIG. 25 is an offset cross-sectional view illustrating the mountassembly of FIGS. 21 and 22 in the open position.

FIG. 26 is an exploded assembly view showing selected components of apreferred closing mechanism.

FIG. 27 is a perspective view illustrating a preferred instrument mountcam post.

FIG. 28 is a perspective view illustrating a preferred instrument mountrelease button.

FIG. 29 is a perspective view illustrating a preferred instrument mountfollower post.

FIG. 30 is a perspective view of a preferred instrument mount shaftclamp.

FIG. 31 is a perspective view of a preferred instrument mount conicalclutch.

FIG. 32 is a perspective view of a threaded collar associated with theinstrument mount shaft clamp.

FIGS. 33 and 34 are exploded perspective and cross-sectional viewsrespectively of a handle mechanism of a preferred tissue stabilizer.

FIG. 35 is an exploded perspective view of a contact member of thestabilizer shown in FIGS. 33 and 34.

FIG. 36 is a rear plan view of the contact member of FIGS. 33, 34 and35.

FIG. 37 is a cross-sectional view of the contact member of FIG. 36 takenalong line 37—37.

FIG. 38 is a perspective view illustrating a stabilizer base embodimenthaving an offset shaft connection.

FIG. 39 is a perspective view illustrating an alternative offsetstabilizer base in use over a target vessel.

FIGS. 40A and 40B are respectively front and side plan views of theoffset stabilizer base embodiment of FIG. 39.

FIG. 41 is a perspective view of a tissue stabilizer having a moveableball/post.

FIG. 42 is a perspective view illustrating another tissue stabilizerembodiment having a moveable ball/post.

FIG. 43 is a partial cross-section taken through the ball/post of FIG.42 showing a spring biased ball/post.

FIG. 44 is a partial cross-section showing the ball/post of FIG. 43utilizing a locking clip to secure the ball/post.

FIG. 45 is a perspective view of the locking clip of FIG. 44.

FIG. 46 is a perspective view illustrating another moveable ball/poststabilizer embodiment.

FIG. 47 is a front perspective exploded view of a stabilizer baseassembly having an adjustable ball/post position.

FIG. 48 is a rear perspective view of the stabilizer base of FIG. 47.

FIGS. 49A and 49B are front and rear perspective views of the stabilizerbase assembly of FIG. 47.

FIG. 50 is a partial cross-sectional view through a portion of the rearguide slot of the stabilizer base of FIG. 47.

FIG. 51A is a perspective view of a stabilizer base embodiment having asingle contact member and bail construction.

FIG. 51B is an end plan view of the stabilizer embodiment of FIG. 51A.

FIG. 52A and 52B are perspective views illustrating another stabilizerbase embodiment having a single contact member and bail construction.

FIGS. 53 and 54 are perspective views illustrating stabilizer baseembodiments having a single contact member and a bail having amechanical drive.

FIG. 55 is a perspective view of a preferred cardiac surgery systemduring operation according to the principles of the present invention.

DETAILED DESCRIPTION

The present invention involves surgical instruments for accessing andstabilizing the heart and methods for their use. The present inventionmay involve a retractor system or assembly for accessing the heart. Thepresent invention may also include a mount that allows variousinstruments to be easily positioned within the surgical working space,locked or secured into a desired position for the duration of aparticular surgical procedure, and then easily and safely removed fromthe working space. According to a preferred embodiment the instrumentmay be a device to facilitate stabilization of the heart during coronarysurgery.

Although the instruments and methods of the present invention may haveapplication in both conventional stopped-heart and beating heartprocedures, they are preferably used to access and stabilize the beatingheart during a minimally invasive coronary artery bypass graft (CABG)operation which has been specially developed to facilitate completion ofan anastomosis, typically between a target artery and a bypass graft orsource artery, without requiring cardiac arrest such as cardioplegia orfibrillation and without cardiopulmonary bypass (CPB). Further, althoughthe instruments for accessing and stabilizing the beating heart can beapplied in a number of different surgical contexts involving variousincisions and surgical approaches to the heart as are known in the art,the instruments and devices described herein are most advantageouslyemployed in a CABG procedure wherein the heart is accessed through onlyone or two minimally invasive incisions in the chest.

Although the particular source vessel and target artery of theanastomosis are determined clinically, a common minimally invasivebypass procedure on the beating heart includes an anastomosis whichforms a connection between the left internal mammary artery (LIMA) asthe source artery, and the left anterior descending artery (LAD) as thetarget artery. To complete the anastomosis, the surgeon must dissect aportion of the LIMA by separating it from the internal chest cavity.Once dissection of the LIMA is achieved, the surgeon may attach thedissected LIMA to the target coronary artery, i.e., the LAD by way ofcreating an anastomosis.

In this example, the present invention may involve a number of discreetcomponents that facilitate access to the anastomosis site, allow variousinstruments or devices to be maneuvered and secured in place, andprovide stabilization of the heart. The retractor of the presentinvention may be used to provide access to the anastomosis site of thetarget artery on the heart itself. The various stabilizer embodiments ofthe present invention may be used to stabilize the beating heart duringat least the portion of the procedure during which the surgeon completesthe anastomosis of the LIMA to the LAD. The mount of the presentinvention may be used to facilitate convenient manipulation of thestabilizer, and other instruments or devices, to their desired positionand allows the devices to be secured in that desired position. Althoughthe LIMA to LAD anastomosis is provided as one example, it is readilyappreciated that the techniques and instruments described herein may beapplied to other procedures depending on the clinical diagnosis and thepatient's anatomy.

Although each component of the present invention may be used separatelywith great benefit, the components are preferably used in unison toprovide a surgical system which provides an unobstructed and organizedsurgical field, exceptional instrument maneuverability and access to theheart facilitating total revascularization of the heart if required, andeffective vessel stabilization during the anastomosis procedure.Although the present invention will have application whether access tothe heart is achieved by way of a full-sternotomy, mini-sternotomy,para-sternotomy, thoracotomy or other known approach, the exemplarembodiments described below will be generally described with referenceto a coronary artery bypass procedure using a mid-sternal approach.

Referring to the figures wherein like numerals indicate like elements,an exemplar surgical system for performing a mid-sternal surgicalprocedure on the beating heart is illustrated in FIG. 1 and includesretractor assembly 10, mount assembly 20 and stabilizer assembly 30.

Retractor assembly 10 generally includes a pair of opposing bladesadapted to engage opposite sides of a sternal incision, or otherincision, and a drive mechanism constructed to force the blades, andthus the sternum apart. Using the drive mechanism, the sternum may bespread to the desired opening, thus providing the desired access anddirect visualization of the thoracic cavity. If desired, the heart maybe positioned or oriented to best present the target vessels foranastomosis. This positioning may be established, for example, throughthe strategic placement and tensioning of sutures in the pericardialsac, by appropriately placing the patient in the Trendelenburg position,or by using a heart positioner in the form or a strap or pad or thelike.

Once the target vessel is in the desired position, at least onecomponent of stabilizer assembly 30 is brought into contact with thebeating heart adjacent the target site of the anastomosis. The surgeonthen applies a stabilizing force to the beating heart via the stabilizerassembly 30 which may then be fixed in place, preferably to theretractor assembly 10 by way of mount assembly 20. The stabilizing forcesupplied by the stabilizer assembly substantially eliminates movement ofthe heart in the area of the anastomosis so that the surgeon mayaccurately and efficiently perform the required anastomosis (or othersurgical procedure). After the anastomosis has been completed, thestabilizing force is released and the contacting component of stabilizerassembly 30 is removed from the anastomotic site.

Each of the principal components, the preferred surgical system, andtheir methods of use are separately described in detail below. Apreferred retractor according to the principles of the present inventionis described below with reference to FIGS. 2-12. A preferred stabilizeror instrument mount according to the principles of the present inventionis described below with reference to FIGS. 13-32. Preferred stabilizerembodiments according to the principles of the present invention aredescribed below with respect to FIGS. 33-44. A preferred surgical systemand methods for performing a coronary artery bypass on a beating heartaccording to the principles of the present invention is described belowwith respect to FIG. 45.

The Retractor

According to the principles of the present invention, the retractorgenerally involves a drive mechanism and a pair of opposing bladesadapted for insertion into an incision and for engaging opposite sidesof the incision. The drive mechanism functions in some manner to urgethe opposing blades apart, thus forcing opposite sides of the incisionopen to allow surgical access through the incision. For purposes ofperforming a coronary artery bypass, the incision may be any suitableincision which provides the desired access to the thoracic cavity, andmore specifically a desired area of the heart. For purposes of exampleonly, the retractor of the present invention will be described withrespect to a mid-sternal incision, however skilled artisans willrecognize that many aspects the invention are equally applicable toother surgical approaches to the heart, for example, by way of athoracotomy, or other suitable access approach.

When the heart is accessed by way of an incision through all or aportion of the sternum, the opposing blades are adapted to be insertedinto and engage opposite sides of a sternal incision such that thesevered sternum may be forced apart by the action of the opposing bladesto create a working space for operating on the heart. Typically, thedrive mechanism is constructed to spread the opposing blades apart in agenerally parallel fashion, however, the parting motion may also have asignificant curvilinear or angular component as well.

In one embodiment, the blades may be permanently, integrally, orinseparably formed with a drive mechanism. Preferably however, at leasta portion of the blades are separable from the drive mechanism. That is,at least some of the features and functions associated with theretractor blades are allocated to a structural component which isseparate, separable, or otherwise detachable from the drive mechanism.The separate component and the drive mechanism may be manufacturedindependently and then subsequently assembled at the factory or, morepreferably, at the point of use.

A retractor construction having a separable component allows thefeatures and functions of the drive mechanism to remain separate fromthe remainder of the retractor assembly and vice versa. This allows agreatly simplified or depopulated drive mechanism and allows theseparable component to have a much more sophisticated construction withincreased features and functionality. Accordingly, the simplified drivemechanism, which is typically required to be made from a hardened steel,is easier and more economical to manufacture and easier to maintain,clean and sterilize post surgically. Moreover, the separate componentcan be economically made from materials or processes that allow for theintricate structural features which provide superior functionality.

In a preferred embodiment, the drive mechanism is constructed to beresterilized and reused a relatively large number of times, and thefeature-rich separate component is constructed to be disposable, i.e.discarded after a single surgical use. Thus, the depopulated drivemechanism, which will be used over and over, can afford to beconstructed to be quite robust with a view to materials andmanufacturing processes that will support the rigors of such extendedsurgical service. The separable component, free from the typicalfunctional requirements of the drive mechanism and the servicerequirements of extended surgical re-use, may preferably be constructedfrom any number of engineering materials to produce an economicalcomponent having the desired features and which may be discarded after asingle use if desired.

In a preferred embodiment, retractor assembly 10 comprises a drive 12and first and second platform blades 14 and 16 detachably connected todrive 12, as illustrated in FIG. 2. Preferably first platform blade 14and second platform blade 16 each have one or more channels or engagingmembers 18 adapted to engage opposite sides of an access incision.Activation of drive 12 forces apart first and second platform blades 14and 16 thereby causing engaging members 18 to correspondingly force theincision open to provide access to the desired surgical site.

In the example of a sternal approach to the heart, engaging members 18are adapted to engage each side of the incised sternum to reliably holdand engage the sternum as the sternum is forced open to expose thethoracic cavity and ultimately the heart. As best seen in FIG. 9, whichillustrates a cross-section of second platform blade 16, engaging member18 is generally in the form of a channel or the like, preferably havinga U-shape, curved shape, or other shape suitable for engaging theincised sternum.

Preferably, engaging member 18 generally has a concave interior profile17 for engaging and holding the sternum and a corresponding convexexterior profile 19 that is relatively smooth so as not to interferewith other surgical instruments, snag sutures or create other suchdifficulties. The engaging members 18 are preferably constructed to havesufficient strength to withstand the loads required to spread thesternum yet maintain a suitably low profile to facilitate easy insertioninto the access incision and to require as little space within theworking incision as possible.

It may be desirable to provide engaging members 18 with features toreduce trauma to the incision site, increase the traction against thesides of the incision, or both. A thin pad or layer of non-slip oratraumatic material (not shown) may be fixed, by way of an adhesive orother suitable fastening technique, to the interior profile 17 ifdesired to reduce slippage and trauma to the severed sternum orsurrounding tissue. Alternatively, the desired features may beintegrally fabricated into engaging members 18. For example, whenplatform blades 14 and 16 are injection molded components, tractionfeatures such as raised bumps, ribs, indentations, or the like can bemolded integral into engaging members 18.

Referring to FIGS. 2-6, drive 12 is preferably constructed to force theplatform blades apart in generally opposite directions. Any type ofdrive mechanism which provides the desired separating action of theblades may be suitable. A common, substantially straight-line partingmotion may be provided by a ratchet or rack arrangement as is generallyknown in the art. FIG. 3 illustrates a preferred drive 12 which involvesa bar 15, moveable housing 22 and handle assembly 24 which facilitatesmovement of moveable housing 22 relative to bar 15. A first end of firstblade 14 may be operably attached to moveable housing 22 and secondblade 16 to bar 15.

In a preferred embodiment, bar 15 is a substantially rigid bar having astationary or fixed housing 21 assembled thereto and thus forming barassembly 23. Fixed housing 21 may be fastened to one end of bar 15 usingone or more mechanical fasteners, an interference fit, suitable adhesiveor bonding compounds, welding, or any other suitable fasteningtechnique. A first end of second blade 16 is preferably operablyattached to fixed housing 21. As with moveable housing 22, fixed housing21 may be of any configuration which provides for the structuralattachment of first and second platform blades 14 and 16.

Bar 15 preferably includes a number of teeth 13 evenly spaced along atleast a portion of its length. Teeth 13 may have substantially parallelside portions 11 and may have radiused tops 25. The exterior edges ofteeth 13 may be broken or radiused or have a chamfer 26 as shown. Handleassembly 24 preferably includes a means for engaging teeth 13 so as todrive moveable housing 22 relative to bar 15 to any desired positionunder load where it remains so positioned against the load without needfor any applied input or holding force. The means for engaging teeth 13could be any suitable gear, ratchet, cog or like mechanism. Bar 15 mayalso be adapted and used for receiving an instrument mount, such asthose described in detail below.

In a preferred embodiment, moveable housing 22 is driven using one ormore drive pins which may successively engage teeth 13 in a coggingmanner. Handle assembly 24 includes drive handle 29 connected to firstand second cylindrical drive bearings 31 and 32. Drive bearing 31preferably has a raised boss 34 extending from one end to which drivehandle 29 may be pivotally connected by way of pin 33. At the oppositeend, drive bearing 31 has first drive pin 27 and second drive pin 28extending therefrom and terminating at second drive bearing 32. Firstand second drive bearings 31 and 32 are spaced apart a distance 35 whichis selected to be slightly greater than the thickness 38 of bar 15 suchthat a portion of bar 15 may be received between first and second drivebearings 31 and 32. The outside diameters of drive bearings 31 and 32are selected so as to fit within guide holes provided in moveablehousing 22. For example, the outside diameter of second drive bearing 32is sized to accurately rotate within guide hole 36.

Moveable housing 22 has a bore 37 extending therethrough for receivingbar 15. Bore 37 generally has a shape corresponding to the dimensions ofthe cross-section of the portion of the bar 15 which is to pass throughbore 36. With handle assembly 24 properly positioned within the guideholes provided in moveable housing 22, it may be assembled to bar 15 byplacing the end of bar 15 within bore 36 and turning handle 29 such thatfirst and second drive pins 27 and 28 become engaged with teeth 13. Onceassembled in this manner, moveable housing 22 may be forced one way orthe other along the length of bar 15 by turning handle 29, and thusdrive bearings 31 and 32, to cause first and second drive pins 27 and 28to progressively engage teeth 13 along bar 15.

As mentioned above, first and second platform blades 14 and 16 may beremovably assembled to moveable housing 22 and fixed housing 21,respectively. Platform blades 14 and 16 may be attached in any suitablefashion including, for example, threaded connections or other matingfeatures on the platform blades and housings themselves, ordinary orspecialized mechanical fasteners, and cam or latching mechanisms adaptedto secure the platform blades to the housings. In a preferredembodiment, both moveable housing 22 and fixed housing 21 areconstructed with features that engage, secure and support first andsecond platform blades 14 and 16 in an operable position on drive 12,thus providing an assembled retractor 10 which is ready for surgicaluse.

Referring to FIGS. 7 and 8, second platform blade 16 is shown before andafter assembly onto fixed housing 21. Preferably, at least one of theplatform blade 16 or the fixed housing 21 has an extending protuberance,post or like feature which can be receivably engaged by the other of theplatform blade or housing. In a preferred embodiment, fixed housing 21is preferably constructed to have a latch post 42 adapted to be receivedwithin latch post cavity 45 provided in platform blade 16. Latch post 42may have a hole, notch, protuberance, or other feature formed thereinwhich may be engaged in any convenient manner by the platform blade 16so that platform blade 16 becomes releasably locked in place for use.

In a preferred embodiment, latch post 16 has a notch which defines latchsurface 51 and stop surface 52. Platform blade 16 has a latch member 48,best seen in FIGS. 11A—11A, having a latch body 50 constructed withsurfaces 53 and 54 for engaging latch surface 51 and stop surface 52respectively. Generally transverse to latch post cavity 45, platformblade 16 has a latch body cavity 56 having an opening towards uppersurface 57 of platform blade 16 for receiving latch body 50 of latch 48.

Latch 48 is preferably constructed to engage and disengage latch post 42by manual rotation of latch knob 49. Latch body 50 includes cylindricalportion 55 which provides for controlled rotation within latch bodycavity 56. Latch body 50 may be biased towards the engaged positionshown in FIG. 8 by way of any suitable spring element. Preferably, latchpost 42 is provided with an angled tip 43 having a lead-in angle 44which allows angled tip 43 to slide against second engaging surface 54as latch post 42 begins to be received within latch post cavity 45. Aslatch post 42 is advanced further within latch post cavity 45, angledtip 43 causes latch 48 to rotate out of the way about cylindricalportion 55. Near the end of the advancement of latch post 42 withinlatch post cavity 45, the angled tip is advanced beyond latch body 50,and latch 48 (which is biased towards an engaged position) rotates intothe engaged position with second engaging surface 54 biased against stopsurface 52.

With latch 48 and latch body 50 snapped into the engaged position, anyseparating force encountered between platform blade 16 and fixed housing21 is resisted by action of first engaging surface 53 against latchsurface 51. With this configuration, the reaction force at firstengaging surface 53 is advantageously borne by latch body 50 primarilyin compression. Thus, since the loading is primarily compressive innature, a high strength material is not required, and latch 48 can bemade from standard engineering polymers, for example, such aspolycarbonate.

When it is desired to remove platform blade 16 from drive 12, theoperator simply turns latch knob 49, causing latch body 50 to be placedin a disengaged position relative to latch post 42. With latch 48disengaged, latch post 42 of fixed housing 21 is free to be removed fromlatch post cavity 45 of platform blade 16. As is apparent from theFigures, a mirror image of the latch assembly described with referenceto platform blade 16 and fixed housing 21 is provided to releasablyattach platform blade 14 to moveable housing 22.

When the retractor assembly is used to gain access to the thoraciccavity, a good deal of force must be generated to create the desiredopening. For example, a separating force in excess of 100 pounds may berequired to be generated at each engaging member 18 to achieve thedesired separation of a particular sternum. Such loads must be carriedby the engaging members and transmitted to drive 12 by way of platformblades 14 and 16. Since platform blades are preferably made from asuitable engineering polymer (for example, a glass filled thermoplasticpolyurethane resin), it may be desirable to provide a reinforcing memberfor each of platform blades 14 and 16 to ensure that platform blades 14and 16 will not break or otherwise rendered inoperable as a result ofthe loads encountered during use.

Although the reinforcing members may be a permanent or removable memberswithin the platform blades themselves, the reinforcing members arepreferably one or more substantially rigid members extending from eachof the fixed housing 21 and the moveable housing 22. In a preferredembodiment, fixed and moveable housings 21 and 22 have a pin extendingtherefrom which may be received within a mating cavity within first andsecond platform blades 14 and 16. The pin operates to spread the loaddeveloped in the mechanism over a larger internal area within theplatform blades 14 and 16 and reduces the effective beam length ofunreinforced platform blade material subjected to the operating loads.The pin may be straight pin 40′ illustrated in FIG. 3. More preferably,fixed and moveable housings 21 and 22 have tapered pins 40 and platformblades 14 and 16 have mating tapered cavities 41 for receiving taperedpins 40. The tapered construction tends to allow the user to easilyalign pin 40 with cavity 41 and allows the pins 40 to fit relativelysnugly within cavities 41 without significant binding during insertionthat could otherwise occur between elongate pins and mating cavitieswhich are designed to be very close fitting.

To provide sufficient load bearing reinforcement, the reinforcing pins40 are preferably constructed of a substantially rigid material, such assteel, and are preferably at least about 0.75 inches long, morepreferably at least about 1.125 inches long, and most preferably betweenabout 1.25 inches to about 2.25 inches long. In a preferred embodiment,reinforcing pins 40 are made from AISI 420 stainless steel having alength of about 1.5 inches, an outside diameter near the housing ofabout 0.25 inches, and a 2 degree taper angle decreasing towards thefree end of the reinforcing pins 40.

In the preferred embodiments just discussed, platform blade 16 can beremoved from drive 12 with a substantially straight-line relative motionas indicated by arrow 46. This engagement action not only provides forsimple and intuitive assembly in the operating room, but also representsa significant safety feature. Under certain rare circumstances, forexample where the drive through neglect or misuse has becomesufficiently damaged during use that it is unable to close and disengagefrom the sternum, an extremely dangerous situation can be created forthe patient. In such exigent circumstances, the configuration describedabove may allow the drive to be separated from the in situ platformblades by releasing the latches and applying a sufficient amount offorce in the direction indicated by arrow 46. Once the drive has beenremoved, the detached platform blades may be easily removed from thepatient.

In addition to engaging members 18, detachable platform blades 14 and 16may incorporate a wide variety of additional features which enhance theperformance of the retractor system. For example, one or both ofplatform blades 14 and 16 may have mounting features to which variousinstruments used during the procedure can be secured. In the case wherea stabilizer is to be secured to a retractor for operating on a beatingheart, it is critical to minimize or substantially eliminate the amountof flex and motion attributable to each component and each connectionbetween each component, from the component engaging the beating heart tothe component which provides the sternal attachment. To this end, theengaging features 18 which engage the sternum are preferably part of aunitary platform blade structure which also includes mounting featuresto which a stabilizer and other instruments can be mounted. Since themounting features and the sternal engaging features are part of the samecomponent, and therefore there is no mechanical connection between thetwo, the stability of an attached instrument against the forces of abeating heart is greatly improved.

In a preferred embodiment, each of first and second platform blades 14and 16 include mount features in the form of rails. The rails allow oneor more instruments to be positioned at any desired location along theoperable length of the rail. Preferably, the rails are oriented in adirection generally perpendicular to the direction of separation, inthis case perpendicular to bar 15. The rails may be a recessed featurewithin the body of platform blades 14 and 16. More preferably, themounting rails extend upwardly from the body of platform blades 14 and16.

Referring to FIGS. 7-9, right platform blade 16 has rail 60 extendingover at least a portion of the length of platform blade 16. Rail 60 mayhave a top portion and a bottom portion having a narrowed regionadjacent said top portion. In one embodiment, Rail 60 preferably has aT-shaped cross-section. The T-shaped configuration has a top portion 61and a narrowed portion 62, thus forming mounting tabs 63 and 64 whichcan be gripped by a number of appropriately constructed mounts.

The rail may be straight, curved, or a combination of straight andcurved portions. Preferably, at least a portion of the T-shaped rail iscurved in a manner which more closely follows the profile of the accessor incision site (as seen, for example, see FIG. 45). In a curved railconfiguration, instruments extending perpendicular to a generallycentral axis 67 of rail 60 will naturally point more towards a centralarea between the platform blades 14 and 16, and thus may require lesspositional adjustment or manipulation from their normal, natural orbeginning position. In addition, all or a portion of top portion 61, andmore specifically mounting tabs 63 and 64, may be tilted or angledinwardly at an angle 65 as shown.

Platform blade 16 may be also be provided with a number of sutureholders or stays which can be used to organize or capture varioussutures used in the course of a particular surgery. Since certainsutures are placed near the beginning of a CABG procedure, such aspericardial sutures used to position the heart, the placement of thesuture stays in a manner which does not interfere with subsequentprocedures and instruments is an important aspect of the presentinvention. Preferably, the suture stays are positioned such that placingand manipulating the sutures or the various instruments and instrumentmounts employed during surgery can be accomplished without interferingwith each other. Preferably, the location of the suture stays positionthe sutures below the level of the mounting tab 63 and 64 so that amating instrument mount may traverse the entire operable length of rail60 without interfering with the sutures.

Rail 60 may have one or more grooves, channels, slots or passageways forreceiving a suture. In addition, a suture lock may be provided in therail or elsewhere on platform blade 16 so that the suture may be fixedin place. To accommodate the use of pericardial sutures, which are oftensubjected to a significant amount of tension when used to position theheart, the suture locks must be adapted to hold the suture material evenwhile under a significant amount of tensile loading.

In a preferred arrangement for organizing and locking sutures, and inparticular tensioned pericardial sutures, rail 60 has at least one openslot or passageway formed therein for receiving the free end portions ofa surgically placed suture. The passageways preferably extend acrossrail 60 and have a depth which allows the suture to lay at an elevationsufficiently below mounting tabs 63 and 64 so as not to interfere withan instrument mount sliding along rail 60. In a preferred embodiment thepassageways extend through at least a portion of narrowed portion 62.Thus, the height 66 of narrowed portion 62 may be selected not only toprovide sufficient space for a desired instrument mount to attach, butalso to ensure that mounting tabs 63 and 64 are sufficiently raisedabove the surrounding features of platform blade 16 so that aninstrument mount may be positioned and repositioned along rail 60without disturbing or disrupting the sutures within the variouspassageways.

The passageways may be a single channel for receiving both free ends ofa surgically placed suture or each end may have a separate channel. In apreferred embodiment, rail 60 has a number of bifurcated channels 70 atpredetermined intervals along its length. Referring to FIG. 10,bifurcated channel 70 has a single entrance channel 71 which bifurcatesinto first and second exit channels 72 and 73. Entrance channel 71 andeither one of exit channel 72 or 73 can be used in the same manner as asingle channel, with both free ends 76 and 77 being routed together.Alternatively, both suture ends may be received within entrance channel71 and then separated, one end within exit channel 72 and one end withinexit channel 73.

A means for clamping the suture against movement within the suturechannels may be provided on any of entrance channel 71 or exit channels72 or 73. Preferably, suture locks are provided on each exit channel 72and 73. This allows the surgeon to positively identify and unlock adesired suture end for further tension adjustments or other manipulationwithout unlocking or loosening the other end of the suture. In addition,placing each suture end 76 and 77 in separate exit channels 72 and 73,each with a dedicated suture lock, increases the maximum amount oftension that can be applied to a given suture. Exit channels 72 and 73may have recesses 74 and 75, respectively associated therewith forreceiving a suture lock adapted to secure the suture material within thechannels.

A preferred suture lock 80 is illustrated in FIGS. 10 and 12. Suturelock 80 has a relatively rigid body 83 having a fixed or pivot end 81which allows body 83 to pivot within the mating profile of recess 74 or75. Pivoting the body 83 about pivot end 81 selectively engages anddisengages free end 84 against the wall 78 of exit channel 72 or 73.Alternatively, suture lock 80 may be made from a more flexible materialwhich, by nature of the elastic properties of the material, tends toflex about its fixed end instead of rotate. In a preferred embodiment,fixed or pivot end 81 is substantially cylindrical and recesses 74 and75 have mating cylindrical surfaces.

Preferably, the suture lock is angled relative to the wall 78 so that itis self-locking in one direction. That is, the suture ends 76 or 77 (orboth) operate on the free end 84 in such a way as to force it towardswall 78, and thus against the suture material, in proportion to thetension, T encountered by suture ends 76 or 77. Thus, within practicallimits, the higher the tension the harder free end 84 will press or biteagainst the sutures placed therein. Conversely, when the suture ends arepulled in the direction indicated by arrow 79, the suture forces tend topivot body 83 about pivot 81 such that free end 84 is rotated away fromwall 84 allowing the suture to move relatively freely. Preferably, angle79 between body 83 and wall 78 is nominally about 1 degree to about 30degrees, more preferably about 5 degrees to about 15 degrees, mostpreferably about 10 degrees. Of course, angle 79 is greater as body 83pivots to accept a suture placed within the suture channel.

Suture lock 80 may be biased towards the locked position, preferablyusing a small spring between the suture lock and the recess 75. In apreferred embodiment, a piece of resilient closed cell foam 85 is fixedto body 83 to provide the desired biasing effect. Free end 84 mayoptionally have a number of teeth or ridges 82 to ensure acceptabletraction against the suture material.

Platform blades 14 and 16 may also be provided with soft tissueretainers to help control and retain the incised tissue and fat in theimmediate vicinity of the blades. Referring to FIGS. 8 and 9, platformblade 16 includes integrally attached tissue retainer 85. Tissueretainer 85 is generally at a small distance 88 above the top of theengaging members 18. Tissue retainer 85 may be made from a flexiblematerial, such as an elastomer, preferably a polyurethane elastomerhaving a durometer in the range of about 45 to about 75 Shore D, morepreferably about 55 Shore D. In a preferred embodiment tissue retainer85 is injection molded over the platform blade to form a permanent andinseparable assembly. Tissue retainer 85 may have a raised outer lip 86and optionally having a plurality of slots 87 formed therein to receiveand organize any loose suture ends. Tissue retainer 85 ensures that thetissue surrounding the access incision does not interfere with theoperation of rail 60 or the suture holders and also provides aconvenient location for attaching surgical drapes of the like withoutinterfering with the operation of the retractor assembly.

Although some of the features of the present invention have beendescribed, for illustration only, with respect to only one of theplatform blades 14 and 16, it should be apparent that both platformblades 14 and 16 may have similar or identical features. Although notnecessarily so, first platform blade 14 and second platform blade 16 arepreferably substantially mirror images of each other.

The retractor assembly just described, provides a simplified drivemechanism for use in conjunction with multi-featured platform blades. Inaddition, a number of different platform blades may be provided for usewith a single drive, for instance, tailored to different sized anatomyor the specifics of different surgical procedures. Thus, a number ofplatform blade configurations can be provided to an operating room and,based upon pertinent prevailing clinical factors, the properconfiguration can be selected, mounted to drive 12, and used asdescribed above to provide access to a desired location. Also, with themodular configuration new features and advancements can be rapidlyincorporated into the platform blades and immediately introduced for usewith existing simplified drives already in place in the operating rooms.

The platform blades themselves represent a surgical platform that allowsinstruments to be mounted and stabilized in virtually any position, evenover already placed and secured sutures from the surgical site accessedby the retractor assembly. Described below are preferred instrumentmounts for use in conjunction with rail 60 to secure a beating heartstabilizer or other instruments such as heart positioners, saline ormedical air blowers, suction devices, surgical clamps, or vesseloccluders.

The Instrument Mount

Referring to FIG. 13, a preferred instrument mount assembly 20 is shownfor mounting an instrument, such as stabilizer assembly 30, to aninstrument mounting rail such as described above with respect to rail 60of platform blades 14 and 16. Mount assembly 20 includes mount base 115having features to secure mount assembly 20 at a desired position on anappropriately configured mating rail or other suitable structure andincludes a shaft locking mechanism for controlling and securing aninstrument shaft in a desired position and orientation.

One important aspect of instrument mount assembly 20 is to provide thenecessary degrees of freedom to allow the instrument to be easilymaneuvered to whatever position may be required by a particularprocedure. As discussed above, an additional aspect with respect tostabilizing the beating heart is to eliminate or minimize the flex ormotion attributable to the various components and connections ofinstrument mount assembly 20. As will be discussed in more detail below,instrument mount assembly 20 is uniquely suited for use in stabilizingthe beating heart because it allows sufficient degrees of freedom toeasily manipulate the position of an instrument secured thereto, allowsthe degrees of freedom to be frozen or locked in place and, once lockedin place, does not significantly flex or allow movement at any of themechanical joints or connections.

Instrument mount assembly 20 provides a number of different controllablejoints that, when in a released condition, allows motion in one or morepredetermined directions or about one or more degrees of freedom.Although instrument mount assembly 20 may be used to secure any mountingshaft configuration from straight or curved substantially rigid shaftsto multi-link or segmented ball and socket type shafts which arerelatively flexible until themselves locked in some manner at each jointalong the shaft length, it is most advantageously constructed to providethe joints or connections required to position an instrument having astraight or curved rigid shaft.

In a preferred embodiment, instrument mount assembly 20 has threereleasable joints or connections for controlling the location andposition of the instrument mount assembly and instrument attachedthereto. The mount base may be positioned at a desired location along anappropriate rail and secured by rail grips 114 and 116. The position andorientation of the instrument is then determined by ball joint (or balland socket joint) 112 between mount base 125 and mount body 110, arotational joint 157 between mount body 110 and shaft hub assembly 160,and a shaft clamping mechanism within shaft hub assembly 160 which mayallow translation, rotation, or both of shaft 3 relative to shaft hubassembly 160.

Ball joint 112 is preferably of the ball and socket type having 3rotational degrees of freedom. Rotational joint 157 allows rotation ofshaft hub assembly 160 about axis 121 as indicated by arrow 113. Theshaft clamping mechanism allows translation of instrument shaft 3 asindicated by arrows 111 as well as rotation about the shaft itself asindicated by arrow 117. As will be discussed later, a further ball-jointtype connection 201 may be employed between shaft 3 and the particularend-effector of the instrument.

Instrument mount assembly 20, having the particular joints andconnections identified above, allows all the required areas of the heartto be conveniently and intuitively accessed by a stabilizer connected toone end of a substantially rigid shaft. Certainly, instrument mountassembly 20 could be provided with more or less degrees of freedom formaneuvering a particular instrument. For example, to add additionaldegrees of freedom rotational joint 157 could be replaced with a balljoint and to eliminate degrees of freedom shaft 3 could be keyed withinshaft hub assembly 160 or ball joint 112 could be replaced with arotation only joint. However, it should be noted that excessive degreesof freedom may tend to make instrument adjustment increasingly difficultand cumbersome to control while too few degrees of freedom may not allowthe instrument to be easily placed in the desired position ororientation.

In one embodiment, the various joints and connections are locked into adesired position by way of a series of knobs. The degrees freedomprovided by ball joint 112 is locked by activation of top mount knob120. Both rotational joint 157 and the shaft clamping mechanism of shafthub assembly 160 is locked in place by the activation of side mount knob118. Base 125 is locked in position on the rail by activation of mountlever 122. Ball joint 201, as will be discussed in greater detail below,may be locked in position by activation of knob 504. This particularsequence of knobs used to lock down the degrees of freedom associatedwith instrument mount assembly 20 tends to allow the user greaterprecision in positioning the instrument because degrees of freedomunnecessary to a particular desired maneuver of the instrument can belocked down. Most commonly, mount body 110 is placed at a desired angleor orientation and then fixed in place by locking ball joint 112,leaving final adjustment to take place using rotational joint 157 andthe shaft movement allowed by the shaft clamping mechanism of shaft hubassembly 160.

FIGS. 14-20 show in greater detail the various mechanisms which lock andrelease the joints or connections associated with instrument mountassembly 20. FIG. 14 shows an exploded assembly illustration ofinstrument mount assembly 20. Instrument mount assembly 20, and morespecifically mount base 125 to which all the other components areultimately secured, is preferably constructed to engage and lock inposition on a rail or other suitable feature.

Preferably, instrument mount assembly 20 has a fixed rail grip 114adapted to engage mounting tab 64 of rail 60 and a moveable rail grip116 adapted to engage mounting tab 63 or rail 60. Rail grips 114 and 116may generally have hook-like features for gripping mounting tabs 63 and64. Rail grip 114 is part of mount base 125 and moveable rail grip 116is part of articulating hinge member 115, which is pivotally attached tomount base 125 by way of hinge pins 123 and 124, or other suitablefastener. Articulation of hinge member 115 and rail grip 116 in clampingmanner towards rail grip 114 on mount base 125 effectively clamps mountbase 125 onto rail 60 at mounting tabs 63 and 64.

Hinge member 115 may be articulated using any suitable mechanism capableof pivoting hinge member 115 to a closed position and holding it there.In a preferred embodiment, best illustrated in FIGS. 15A-17, hingemember 115 includes follower surface 155 which may be acted upon by anysuitable cam device to drive hinge member 115 about hinge pins 123 and124, thus urging rail grip 116 towards rail grip 114.

In a preferred embodiment, hinge member 115 is articulated by action ofcam 145 having cam surface 152 which acts upon follower surface 155. Cam145 has a center, C about which cam 145 rotates. Preferably, cam 145 hasbore 127, having its central axis coincident with center, C. Mount base125 may have a cam guide 153 around which bore 127 rides for smoothrotation of cam 45 about center, C. Cam surface 152 has a varyingradius, illustrated by exemplar radial lines R₁, R₂, R₃, R₄, and R₅.Thus as cam surface 152 is rotated past follower surface 155, fromexample from R1 to R2, it pushes the follower surface a greater distanceaway from center, C, thus causing hinge member 115 to pivot about hingepins 123 and 124, thus causing rail grip 116 to move closer to rail grip114.

The varying radius of cam surface 152 may be configured to place hingemember 115, and thus rail grip 116 in a variety of positions. A firstportion of cam surface 152 may be configured such that follower surface155 biased against cam surface 152 is placed in an positioncharacterized in that rail grip 116 is sufficiently spaced apartrelative to rail grip 114 to allow assembly onto a rail or otherstructure. A second portion of cam surface 152 has an increasing radiussuch that rotation of cam 145 moves rail grip 116 towards rail grip 114to an intermediate position. In the intermediate position, rail grip 116has been moved close enough to rail grip 114 so that it becomes capturedon a rail but remains loose enough to slide along the rail. A thirdportion of cam surface 152 has an increasing radius such that therotation of cam 145 moves rail grip 116 further towards rail grip 114 toa completely locked position wherein relative motion between rail grips114, 116 and the rail is essentially no longer possible.

Cam 145 is generally provided with a handle or lever 122 to allow theuser to easily turn cam 145 relative to mount base 125. Cam 145 may becaptured onto mount base 125 by operation of retaining hook 150 on cam145 which rides within exterior groove 151 on mount base 125 on oneside, and projection 154 which is engaged below undercut 156 generallyopposite to retaining hook 150. Projection 154 also serves to workagainst undercut 156 to return hinge member 115 to the open position ascam 145 is rotated in the opposite (open) direction. Hinge member 115preferably has first and second end stops 158 and 159 between which themotion of projection 154 (and thus the rotation of cam 145) is limited.Cam 145 may also have a protective extended portion or cover 163 whichshields the area of groove 151 when assembled over mount base 125.

The assembly of cam 145 and hinge member 115 to mount base 125 isillustrated in FIGS. 15A and 15B. Cam 145 is placed in position relativeto hinge member 115 with projection 154 in place below undercut 156. Inroughly that position, cam 145 and hinge member 115 are brought overmount base 125 until bore 127 is properly seated over cam guide 153 andretaining hook 150 is positioned within groove 151. Pins 123 and 124 arethen pressed in place through holes provided in both mount base 125 andhinge member 115.

Ball joint 112 is generally created between ball 129 provided at the topof mount base 125 and a socket or mating cavity within mount body 110adapted to receive at least a portion of ball 129. Preferably ball 129includes a generally spherical portion, although other curved shapesproviding the desired degrees of freedom may also be suitable. Base post130 extends vertically upward through bore 126 of mount base 125 andvertical passageway 128 of mount body 110 until enlarged end portion 130become biased against mount base 125. Top mount knob 120 may then bethreaded onto threaded shaft 132 whereby mount base 125 and mount body110, with ball 129 received within mount base 125, becomes capturedbetween top mount knob 120 and enlarged end portion 130. Continuedtightening of top mount knob 120 over threaded shaft 132 forces ball 129harder against mount body 110 until the friction between mating surfaceson ball 129 and mount body 110 become so great as to effectively resistany relative movement, thus locking ball joint 112.

The assembly of rotational joint 157 and shaft hub assembly 160 areshown in FIG. 19. Rotational joint 157 is in the form of a conicalclutch formed between frustoconical surface 138 of clutch member 135 andmating frustoconical surface 139 in mount body 110. Shaft hub assembly160 is generally formed as upper and lower shaft locks 136 and 137 areadvanced over shaft grip 140 and against instrument shaft 3 which ispositioned between shaft locks 136 and 137 and outer shaft guide 144. Asclutch member 135 is received over the outside diameter of grip housing141 of shaft grip 140 tang 164 becomes engaged between upper shaft lock136 and lower shaft lock 137 thereby preventing relative rotationbetween clutch member 135 and shaft grip 140.

Side mount knob 118 having threaded shaft 119 extends through mount body110 (and consequently through transverse bore 131 in central portion 167of base post 130), clutch member 135 and into interior threads 142within grip housing 141 of shaft grip 140. Tightening of side mount knob118 clamps the assembly together. Thus, translation and rotation ofinstrument shaft 3 is prevented as shaft grip 140 and clutch member 135are forced together to clamp or trap instrument shaft 3 between shaftlocks 136 and 137 and outer shaft guide 144. Also, relative rotationbetween frustoconical surface 138 of clutch member 135 and matingfrustoconical surface 139 in mount body 110 is prevented as clutchmember 135 is forced against mount body 110. One or both offrustoconical surface 138 and mating frustoconical surface 139 mayinclude a number of teeth, ridges, or other features to prevent rotationwhen clutch member 135 is forced against mount body 110.

So that the shaft does not become too loose as side mount knob 118 isloosened, a minimum amount of friction between instrument shaft 3 andthe clamping surfaces 146 of outer shaft guide 144 is preferablymaintained by providing a biasing load against shaft 3. Referring toFIG. 20, shaft biasing member 147 is provided within shaft grip 140 tomaintains a biasing load against shaft 3. Shaft biasing member 147 has afirst portion 148 which slides within counterbore 143 in shaft grip 140.Shaft biasing member 147 may optionally have a second portion 149 havingexternal dimensions sized to be received within the inside diameter ofcompression spring 133. Compression spring 133 urges end 134 of shaftbiasing member 147 against shaft 3 to force shaft 3 against clampingsurfaces 146. The amount of force is selected to allow instrument shaft3 to be easily positioned by hand but would generally not allowinstrument shaft 3 to slide relative to shaft grip 140 under only itsown weight.

Referring to FIG. 21 a preferred instrument mount assembly 20 is shownfixed to a preferred platform blade 16 having rail 60. As discussedabove, rail 60 has mounting tabs 63 and 64 over which rail grips 114 and116 may be secured. Instrument mount assembly 20 can be positioned,maneuvered, and removed virtually anywhere along rail 60 withoutdisturbing suture 166 locked in place by free end 84 of suture lock 80below the operating features of instrument mount assembly 20 within anyone of the suture channels provided in platform blade 16. In addition,rail 60 is placed in close proximity to engaging member 18 and thusclose to the surgical opening into the patient providing a more directaccess to the heart by an instrument mounted to instrument mountassembly 20. Since the rail 60 moves in unison with platform blade 16,this relationship between rail 60 and engaging member 18 is maintainedno matter how much or how little platform blades 14 and 16 have beenspread to create the desired surgical opening.

FIGS. 22A-32 illustrate a preferred embodiment of an alternativeinstrument mount assembly 220. Preferably, the degrees of freedomavailable for maneuvering instrument mount 220 is substantially the sameas that of instrument mount assembly 20. Instrument mount assembly 220preferably has ball joint 112 between mount base 221 and mount body 222,a rotational joint 157 between mount body 222, and a shaft hub assembly227 which allows rotation and translation of an instrument shaft heldbetween shaft grip 226 and clutch member 226 of shaft hub assembly 227.Instrument mount assembly 220, however, has a different mechanism forcontrolling or locking the various joints and connections and may alsoprovide a means for releasing and removing the shaft from the bulk ofthe remainder of instrument mount assembly 220.

As just mentioned, the joints and connections themselves are quitesimilar between instrument mount assemblies 20 and 220. As before, balljoint 112 is a ball and socket configuration created between generallyspherical ball 224 provided at the top of mount base 221 and a matingcavity within mount body 222 adapted to receive and slide against atleast a portion of ball 224. Rotational joint 157 may be in the form ofa conical clutch formed between frustoconical surface 243 of clutchmember 225 and mating frustoconical surface 244 in mount body 222. Aninstrument shaft may be clamped in place within shaft hub assembly 227by forcing together shaft grip 226 and clutch member 225 thus closingclamp surface 239 of outer shaft guide 233 towards V-shaped channels 273on shaft locks 231 and 232.

Instead of locking the joints and connections by way of multiple knobsas described above with respect to instrument mount assembly 20,instrument mount assembly 220 preferably uses a mechanism which releaseseach of ball joint 112, rotational joint 157, and the shaft clampingmechanism of shaft hub assembly 227 by activation of a single knob,lever, or other suitable manual interface. Generally speaking, this isaccomplished by utilizing the clamping motion required to lock one ormore of the joints or connections along a first axis to also lock theremainder of the joints or connections along remaining axes.

In a preferred embodiment, ball 224 of mount base 221 is locked in placerelative to housing 222 by operation of base post 230. Base post 230 isassembled through mount base 221 and mount body 222 from the bottomuntil bottom flange 259 (see FIG. 27) is resisted against mount base221. At the top of base post 230 is upper link portion 256 having pivothole 257. Cam 235 is attached through pivot hole 257 at off-center linkpivot 238 using a pin or other suitable fastener and is supported bycontact surface 236 associated with mount body 222. Contact surface 236may be an integral feature of mount body 222 or may be in a separatemount body cover 254 which may be selected to have superior wearcharacteristics.

With cam 235 in a closed position, as shown in FIG. 24, link pivot 238is drawn to its maximum distance 251 (or slightly less than the maximumif the cam is constructed to rotate over center) from contact surface236 thus increasing the clamping force between mount body 222 and ball224 as the assembly is clamped between cam 235 on the top and bottomflange 259 on the bottom. With cam 235 in the closed position, balljoint 112 is effectively locked.

By rotating cam 235, by way of handle 237, to an open position asillustrated in FIG. 25, link pivot 238 is withdrawn to a position closerto contact surface 236 at a distance 252, thus reducing or relaxing theclamping forces between mount body 222 and ball 224 of mount base 221.With cam 235 in the open position, the friction at ball 224 is reducedto a level that allows the user to easily manipulate mount body 222relative to mount base 221.

Mount base 221 may have an insert 253 secured in the bottom thereofagainst which bottom flange 259 is caused to seat as upper link portion256 is drawn upwards by operation of cam 235. Preferably, insert 253includes recess 255 for receiving compression spring 248 captured aboutbase post 230. Compression spring 248 operates between insert 253, andthus mount base 221, and bottom flange 259 to bias base post 230 towardsthe unlocked position.

That same motion of base post 230, created by operation of cam 235, ispreferably also used to lock both rotational joint 157 and theinstrument shaft clamping mechanism of shaft hub assembly 227. Insteadof using a threaded shaft to clamp instrument mount assembly along thisaxis as did the previous embodiment, instrument mount assembly 220preferably utilizes tie pin 240 which is driven in the direction ofarrow 245 causing shaft grip 226 and clutch member 225 to be forcedtogether to clamp an instrument shaft placed therein and also causingfrustoconical surface 243 of clutch member 225 to forced againstfrustoconical surface 244 in mount body 222.

Tie pin 240 preferably has a generally cylindrical back portion 261 anda front portion which is connected in some manner to shaft grip 226.Preferably, the front portion includes forward extending first andsecond flexible prongs 262 and 263. Cylindrical back portion 261 isslidably received within blind hole 272 of release button 242 and ispreferably biased in the unlocked direction indicated by arrow 270 bycompression spring 247 positioned within blind hole 272 behind tie pin240.

Tie pin 240 is preferably driven in the direction of arrow 245 by themovement of base post 230 which is assembled in the space between firstand second prongs 262 and 263 of tie pin 240. Preferably, base post 230has an angled cam or ramp 258 that engages back wall 269 at the base offirst and second prongs 262 and 263. As base post 230 is drawn upwardsin the direction of arrow 271 by cam 235 from the open position of FIG.25 to the closed position of FIG. 24, ramp 258 progressively forces backwall 269, and thus tie pin 240, in the direction of indicated by arrow245.

Tie pin 240, connected at its front end to shaft grip 226, locks aninstrument shaft in place and locks rotational joint 157 in the samemanner as did threaded shaft 119 of instrument mount assembly 20. Insum, tie pin 240 urges shaft grip 226 towards clutch member 225 andmount body 222. The movement of shaft grip 226, having tang 236 engagedbetween upper and lower shaft locks 231 and 232 of clutch member 225,closes together in a clamping fashion surfaces 239 on shaft grip 226 andV-shaped channels 273 on clutch member 225. At the same time, shaft grip226 pushes against clutch member 225 to force frustoconical surface 243against mating frustoconical surface 244 with sufficient force tofrictionally lock the surfaces together, thus preventing relative motiontherebetween.

The operation of cam 235 has been described as generally moving betweenan open position, in which the various joints and connections ofinstrument mount assembly 220 are free to be easily manipulated abouttheir respective degrees of freedom, and a closed position in which thejoints and connections resist any relative movement and are thuseffectively locked in position. However, the outer cam profile of cam235 operating against contact surface 236 may be given a profile thathas one or more intermediate positions such that link pivot 238 isplaced at an intermediate distance from contact surface 236. In anintermediate position, the joints and connections may be in a stiffenedor partially locked state which allows some positional and orientationalmanipulation with somewhat higher operator forces that the completelyreleased condition. In addition, the action of base post 230 may be suchthat ball joint 112 becomes fully locked before tie pin 240 hascompletely locked the remaining degrees of freedom. Thus, cam 235 mayhave a completely released position where manipulation about all degreesof freedom is easily accomplished, an intermediate position in whichonly ball joint 112 is fully locked and the remaining degrees of freedomare unlocked or may be partially locked, and final closed position inwhich all degrees of freedom are locked.

Instrument mount assembly 220 may optionally be provided with a releasemechanism allowing shaft grip 226, and thus the instrument shaftslidably assembled therein, to be released from instrument mountassembly 220 preferably by activation of release button 242. This allowsinstruments associated with instrument mount assembly 220 to be quicklyand conveniently removed and replaced or exchanged.

In a preferred embodiment, first and second prongs 262 and 263 of tiepin 240 have first and second projections 267 and 268 which releasablyattach tie pin 240 to shaft grip 226. Grip housing 274 of shaft grip 226is covered with a sleeve having a deep counterbore 278 and small throughhole 279. The depth of counterbore 278 is longer than the exterior ofgrip housing 274 so as to form internal space 290 (see FIG. 25) whenassembled. First and second prongs 262 and 263 can be flexed to positionprojections 267 and 268 relatively close together for insertion throughhole 279 where projections 267 and 268 can then expand apart lockingprojections 267 and 268 behind surface 280.

Preferably, projections 267 and 268 have lead-ins 291 and 292 whichurged projections 267 and 268 together as they are advanced through hole279 so that shaft grip 226 can simply be aligned with lead-ins 292 and292 and then snapped into place without any further action. Alignment ofhole 279 is generally quite simply accomplished as the cylindricalexterior surface 277 of sleeve 260 is slidably received in asubstantially coaxial arrangement within center bore 219 of clutchmember 225. Clutch member 225 may optionally have first and secondflexures 281 and 282 having first and second retaining features 283 and284 so that it may be snapped in place and thereafter retained withinmount body 222.

As mentioned above, shaft grip 226 may be released from tie pin 240. Toseparate tie pin 240, it is necessary to flex first and second prongs262 and 263 together so that projections 267 and 268 will again bepositioned to fit through hole 280. This may be accomplished byproviding a raised portion 264 having a ramp 266 on tie pin 240. Asliding member may be advanced up tie pin 240 and over ramp 266 andraised portion 264 thus flexing prongs 262 and 263 inwards. Preferably,the sliding member is a tip portion 289 of release button 242. Tie pin240 is slidably received within blind hole 272 of release button 242.The internal diameter of blind hole 272 is small enough so that when itis advanced over ramp 266 and/or raised portion 264, prongs 262 and 263are flexed inwards. Preferably, the entrance to blind hole 272 has aninternal chamfer 288 so that ramp 266 is smoothly engaged as releasebutton 242 is advanced.

Release button 242 preferably has a generally cylindrical body 285 whichis slidably received within mating bore 294 (see FIG. 25) of mount body222. Release button 242 is retained in place, and its sliding travellimited, by release button flange 241 on one end and spring clip ore-clip 293 assembled within e-clip groove 286 on the other end. Springmaterial 246, such as a wave spring washer or foam material, may bedisposed between release button flange 241 and mount body 222 to biasrelease button 242 outwards. Transverse to blind hole 272 tip portion289 also has a clearance slot 287 through which base post 230 passes.

For clarity only, FIGS. 22A-25 have illustrated instrument mountassembly 220 without hinge member 115 and cam 145 attached. However,hinge member 115 having rail grip 116 is preferably pivotally mounted,with cam 145 in place, by way of pins or the like at hinge mount 228 asdescribed above with reference to instrument mount assembly 20. Asdiscussed above, cam 145 may be rotated about cam guide 223 using baselever 122 to secure the instrument mount to a rail or other suitablestructure.

The retractor and instrument mounts described above can be used to mountand stabilize a great number of instruments for use during surgery.Preferably, the retractor and instrument mounts are used to mount amechanical stabilizer for stabilizing at least a portion of the beatingheart during CABG surgery or the like. Described below are a number ofmechanical stabilizer embodiments that are particularly beneficial forstabilizing the beating heart, especially when used in conjunction withthe retractors and instrument mounts described above.

Tissue Stabilizers

Once access to the heart is achieved, and the heart is positioned ifnecessary, a means for stabilizing the beating heart is introducedthrough the opening created and at least one component of thestabilizing device of the invention is brought into contact with thebeating heart. The surgeon then applies a stabilizing force to thebeating heart via the stabilizing means which may then be fixed in placeby attachment to a fixed support. When a retractor or platform is fixedin an open position to expose the heart, the retractor platform may alsoprovide the stable support structure to which the stabilizing means isaffixed. When the position of the stabilizing means is fixed byattachment to a stable support or to the retractor platform, thestabilizing force is maintained for the duration of the procedure.

The structure of the portion of the stabilizing means which contacts theheart may include one or more contact members which exert a stabilizingforce on the heart proximate to the site of the anastomosis. A pair ofcontact members may be plates or rectangular members which are placed oneither side of the target coronary artery at the site of the anastomosisand which may have friction means or tissue spreading or compressingapparatus associated therewith. The contact members may also be providedby a platform which may be substantially planar or which may becontoured to fit conformingly on the surface of the heart. Thestabilizing means may also include a shaft means having severalalternative embodiments to facilitate adjusting the position andorientation of the instrument. For example, the shaft means may have anadjustable length and the axis of the shaft means may have at least oneball joint disposed within its length such that the orientation of theshaft means relative to another structure such as the contact members orstable support may be continuously varied. As is apparent from thedescription of the several embodiments, each of the individualembodiments described and illustrated herein has discrete components andfeatures which may be readily separated from or combined with thefeatures of any of the other several embodiments.

Referring to FIGS. 33-37, a preferred stabilizer assembly forstabilizing the beating heart is comprised of a foot or base portion 553attached to a rigid or semi-rigid shaft means or connecting shaft 3.Base portion 553 typically has one or more contact members 1 adapted tocontact the heart adjacent the site desired to be stabilized. Thecontact members 1 may be substantially planar, may be slightly curved toconform to the shape of the heart, or may be a non-conforming curve toestablish contact between only a portion of the contact member 1 and thebeating heart. The shape of the contact members may be varied dependingon the clinical assessment by the surgeon, the design of the otherfeatures of the stabilizing means, or the design of other instrumentsused to complete the anastomosis. In some embodiments the contactmembers 1 may have apertures, openings or attachments to facilitateconnection with sutures or other devices to achieve the requisitestabilization, occlusion of the target vessel, or exposure of the targetvessel. Examples of suitable base portions and contact members can befound, for example, in co-pending U.S. patent application Ser. No.08/931,158 filed on Sep. 16, 1997, entitled “SURGICAL INSTRUMENTS ANDPROCEDURES FOR STABILIZING THE BEATING HEART DURING CORONARY ARTERYBYPASS GRAFT SURGERY”, the entirety of which is herein incorporated byreference.

Referring to FIGS. 33 and 34, the proximal end of connecting shaft 3 hashandle mechanism 468 assembled thereto which, among other things,provides the user with a means for locking an end effector operablyattached to the distal end of connecting shaft 3. The mechanism 468 isrotatably secured to the proximal end of the shaft means 3 and is formedat a selected angle to the shaft means to permit a surgeon to swivel themechanism to a preferred position where the knob 504 is more readilyaccessible to allow quickly locking the shaft means 3 in the orientationselected. In addition, the angled axis of the knob 504 relative to theshaft means 3 reduces the tendency of the shaft means 3 to rotate aboutits axis when a surgeon applies torque to the knob 504 to lock theassociated locking mechanism. The knob 504 is secured to a screw 539 bysuitable means such as press fitting, bonding, etc. Right and lefthandle covers 540,541 comprise the handle 503 and provide the supportfor the handle mechanism. When assembled, the covers define generally acylinder formed with a selected curvature. A secondary inner molding,generally indicated at 542, includes various integrally formed annularwalls and shoulders for supporting and containing the knob 504 and screw539, as well as a cooperating nut 543, and arcuate wedge 544, a shaftretaining ring 545, the proximal end of the shaft means 3, and aproximal end of the translatable pushrod 505. The proximal end of theshaft means 3 includes an annular retaining ring slot 546 which securesthe proximal end of the shaft means 3 within suitable annular walls inthe corresponding end of the handle covers 540,541 when the retainingring 545, confined by shoulders in the inner molding 542, is snappedinto the slot 546 and the covers are assembled. The nut 543 is confinedby shoulders in the inner molding 542, and the arcuate wedge 544 isslidably confined by correspondingly arcuate walls 547 also formed inthe inner molding.

As may be seen, rotation of the threaded screw 539 within the confinedthreaded nut 543, causes translation of the screw, pivoting and thustranslation of the translatable wedge 544 which abuts the screw, andtranslation of the pushrod 505 which abuts the translatable wedge. As isfurther described relative to FIGS. 35-37, any tightening or looseningof the screw 539, however slight, will cause a corresponding translationof the pushrod 505 into or out of the shaft means 3.

As depicted in the Figures, the shaft means 3 and thus the pushrod 505,are formed with a slight arcuate configuration, which permits additionaldegrees of freedom and movement and orientation of the distal end of theshaft means 3 and thus of the heart contact member 1. Rotation of theshaft means 3 about the axis of confinement within the shaft grip 495 or495 a, moves the distal end of the shaft means 3 through a circular pathwhile changing the angles through which the contact member 1 can beoriented. This allows a surgeon to conveniently achieve a wider range ofpositions and orientations of the contact member relative to thepatient's heart, while keeping the proximal end of the shaft means 3 andhandle mechanism 468 out of the way as much as possible.

FIGS. 35-37 illustrate an associated mechanism for maneuverablysupporting the various embodiments of the contact member 1 and forcooperatively assisting in the quick locking of the contact member by apartial rotation of the knob 504 once the member is positioned. To thisend, the distal end of the shaft means 3 is provided with exteriorthreads matching interior threads in a ball/socket 548. The distal endof ball/socket 548 is provided with slots 549, whereby the remainingmaterial comprises short extended tips 550 which, when bent in orinwardly formed, form a socket. A ball/post 551 includes a ball at oneend and a post at the other. When the mechanism is assembled, theball/post 551 is inserted into place within the ball/socket 548 with theball in the socket and the post protruding from the ball socket. Amechanism for providing a preloaded source, such as a compression spring552, is coupled to the ball/socket 548 abutting the ball. The spring 552is urged by the distal end of the shaft means 3 to exert a preloaded orconstant minimum force against the ball of the ball/post 551. The postof the ball/post 551 is solidly fixed as by pressing fitting, welding,etc., to the contact member 1. The distal end of the pushrod 505 passesthrough the spring 552 to abut the ball of the ball/post 551. Thus whenthe screw 539 is not tightened, the distal end of the pushrod 505 exertsa slight pressure against the ball, however the spring 552 maintains apreloaded force against the ball sufficient to maintain the contactmember 1 at any orientation set by a surgeon. When the screw 539 istightened, the pushrod 505 is forced against the ball to prevent anyfurther movement of the contact member 1. As may be seen, the contactmember 1 can be tilted to assume many orientations since the narrowcenter of the post can tilt into any of the four slots 549 in theball/socket 548. In addition, simultaneous rotation of the curved shaftmeans 3 provides a surgeon with an even greater variety of orientationsof the contact member relative to a patient's heart.

The contact member 1 includes a preferred configuration which improvesthe size of the area of the heart which is visible to a surgeon whilestill providing the required suppression of heart movement necessary toenable the efficient construction of the anastomosis. More particularly,the pair of spaced-apart contact members 1 extend from a common baseportion 553, which uniquely first extends back away from the tips of thecontact members at the point of attachment to the post, as shown atreference number 554. The spaced contact members 1 then curve downwardaway from the common base portion 553 and back past the post and awayfrom the shaft means 3. As may be seen in the FIGS. 35-37, the contactmember 1 of this embodiment uniquely is attached to the post on the samesurface as the surface that bears against the surface of the beatingheart. Since the members 1 separate at the base portion 553 at a point555 behind the distal end of the shaft means 3, a surgeon has anunobstructed and thus optimum view of the heart even below the distalend of the shaft means 3.

The contact members preferably include friction means 556 selectivelysecured to the bottom surfaces thereof to more securely engage a beatingheart. In addition, the tips of the contact members are bent upward inthe form of “ski tips” to lessen their impact when the contact membersare firmly pressed against a beating heart to suppress the anastomoticsite.

Although screw means 539/504/543 is illustrated herein as a lockingmechanism of the handle mechanism 468, it is to be understood that othermechanisms may be employed. For example, a cam/lever mechanism may beattached to a rod which in turn imparts a pivoting movement ortranslation to a suitable bellcrank or pivotable member, which in turnimparts translation to pushrod 505 of the shaft means 3. Thus, lockingmechanisms other than those specifically described herein may be used.

The basic configuration as just described with reference to base portion553 provides the maneuverability necessary to access and stabilize anydesired vessel on the surface of the beating heart. However, the exactmanner and position in which the stabilizer may be placed relative tothe vessel and the surgical techniques preferred by an individualsurgeon may vary significantly. Accordingly, there is some potentialthat certain combinations of stabilizer positioning may interferesomewhat with the preferred surgical technique of a particular surgeon.The embodiments illustrated below with respect to FIGS. 38-40B alleviateany such problems.

One useful variation, as illustrated in FIG. 38, connects connectingshaft 3 to the base portion of the stabilizer at a position which isgenerally offset from the center or off-center. Base portion 710 isagain typically formed of a unitary piece of sheet material and has acurved back portion in which connecting shaft 3 is attached to anextension of the same surface which carries the contacting members,except that the connecting point 718, to which ball/post 551 is attachedis positioned away from the center and therefore away from the spacebetween contact members 712 where the anastomosis would be performed.This configuration tends to ensure that connecting shaft 3 will notinterfere with the surgical access to the center area of the baseportion. Of course, the connection can be offset from the central regionin either direction.

In addition, base portion 710 illustrates a number of features forimproving the traction and vessel presentation during a CABG procedureon a beating heart. Contact members 712 of base member 710 have portions713 having an increased width and which are preferably substantiallyflat or slightly curved to conform to the heart. This configurationprovides a larger area for coined regions 715, which representindentations on the bottom surface for receiving a traction material,thus providing greater traction against the surface of the heart.

Further, base portion 710 provides a smaller open space between contactmembers 712. In a preferred embodiment, the spacing 716 between contactmembers 712 is less than about 0.350 inches, more preferably less thanabout 0.300 inches, and most preferably about 0.25 inches. Thisminimized spacing provides stabilization closer to the vessel and, insome instances, the compressive forces applied through contact members712 actually tend to present the vessel upwards between contact members712 in a more favorably pronounced manner. The tip portions 714 ofcontact members 712 are angled upwards from the surface of the heart tominimize any possible trauma to the heart during use.

As just discussed, the base portions (550 or 710) can be manipulated ororiented relative to the end of the connecting shaft 3 by virtue of theball and socket joint between base portion 553 and connecting shaft 3.The amount of angular manipulation or travel available is somewhatlimited as ball/post 551 eventually bottoms out or stops against eitherthe bottom of slots 549 or extended tips 550. Thus, the contact membershave a limited range of movement relative to connecting shaft 3 basedupon the nominal mounting relationship between the contact members andthe ball/post. Accordingly, for some procedures, it may be desirable tohave a different nominal relationship between the contact members andthe ball/post to shaft connection.

Referring to FIGS. 39-40B, base member 720 illustrates an alternativeorientation of ball/post 551. Instead of being angled away from thecontact members, base member 720 has a back portion 721 which allowsball/socket 551 to be mounted generally parallel to contact members 722.Ball/post 551 preferably extend towards contact members 722 as shown,but may also extend the opposite direction away from the contactmembers. The connecting point 723 is preferably offset a distance 724from the central area between the contact members 722. The connectingpoint 723 is also off set a greater distance 726 from the contactingplace of contact members 722. In nominal position of base portion 722relative to ball/post 551, this configuration tends to keep theconnecting shaft 3 clear from the central portion between contactmembers 722. Furthermore, relative to connecting shaft 3, contactmembers 722 can be maneuvered through a range of motion different frombase member 553 due to the initial orientation of ball/post 551.

Because the preferred location of the attachment of the connecting shaft3 to the base portion may be different from surgeon to surgeon and fromprocedure to procedure, it may be desirable to have the ball/postmoveable to more than one location. In one embodiment shown in FIG. 41,for example, ball/post 562 has threaded end 561 which may be threadedinto any desired threaded receiving hole 563 provided in stabilizer base560. Ball post 564 is preferably provided with one or more flats 564 onthe exterior thereof to facilitate tightening or loosening of thethreaded connection. In the embodiment shown, stabilizer base 560 hasthreaded receiving holes 563 to provide center, offset right, and offsetleft connecting positions.

Referring to FIGS. 42 and 43, ball/post 572 may be captured within slot571 formed in stabilizer base 570. Slot 571 preferably has two or morepositions where the ball/post can be positively locked. In a preferredembodiment, slot 571 preferably has two or more key-hole openings 573.Key openings 573 are sized to receive first post portion 577 having anoutside diameter which closely matches the inside dimension of keyopening 573. First post portion 577 of ball/post 572 is released fromkey hole 573 by pulling ball post in the direction indicated by arrow579 until second post portion 578 is positioned within keyhole 573.Second post portion 578 is sized to have an outside diameter smallenough to fit and traverse through slot 571. Ball/post 572 may then betraversed along the path defined by slot 571 until the next desired keyhole is reached, which may then be engaged by first post portion 577 tosecure ball/post 572 in position on stabilizer base 570.

First post portion 577 may be kept in engagement with keyholes 573 byany convenient manner. For example, ball/post 572 may be spring biasedin the locked position between upper flange 574 and lower flange 575,preferably using spring washers 576 as shown. Ball/post 572 may also belocked into operating position within keyholes 573 by using a retainingor locking clip, such as locking clip 580 illustrated with reference toFIGS. 44 and 45. Locking clip 580 has slot 584 adapted to slide oversecond post portion 578. Locking clip 580 includes a thin portion 585, athick portion 583, a transition ramp 582 between thin portion 585 andthick portion 583, and a grip or handle portion 581. With locking clip580 in the open position shown in FIG. 44, ball post 572 is free to moveupwards in the direction of arrow 579, thus releasing first post portion577 from key hole 573. When locking clip 580 is moved in the directionindicated by arrow 586, the outer thickness of thick portion 583 iswedged between lower flange 575 and stabilizer base 570, thus lockingball/post 572 in place within keyhole 573.

Stabilizer base 590 in FIG. 46 has ball/post 592 mounted to anarticulating member which is moveable between two or more positions.Preferably, ball/post 592 is mounted on first end 594 of pivoting link591 which is pivotably attached to stabilizer base 590 at pivot pin 596.Preferably, pivot pin 596 is centrally located on pivoting link 591. Atsecond end 593 of pivoting link 591, a locking knob 595 may be providedto engage stabilizer base 590. Preferably, locking knob 595 has athreaded shaft or other such fastening or locking feature which engagesmating threaded holes (typically one positioned under locking knob 595and one under ball/post 592) in stabilizer base 590. The ball/post 592and locking knob 595 are preferably spaced equal distances from pivotpin 596 such that when pivoting link 591 is rotated as indicated byarrow 597, the position of ball/post 592 and locking knob 595 arereversed.

Another embodiment of a tissue stabilizer having an adjustableattachment position of the connecting shaft is illustrated in FIGS.47-50. Stabilizer base assembly 625 includes top member 605 andstabilizer base 600, having contact members 606 and 607 and notch orrelief 603 under which a vessel may safely pass without being occluded.At least a portion of stabilizer base 600 has outer profile 601 which isgenerally curved or circular at a predetermined radius. Top member 605has a mating interior curvature such that stabilizer base 600 and topmember 605 concentrically rotate relative to each other, preferablyabout a common center point. Ball/post 602 may be attached at aconvenient position, typically centered, on top member 605. Rotation oftop member 605 relative to stabilizer base 600, as indicated by arrows620 and 619, thus adjusts the position of ball/post 602 along an arcuatepath relative to contact members 606 and 607.

To facilitate the secure attachment and smooth rotation of top member605 relative to stabilizer base 600, top member 605 may be provided withone or more projections adapted to be received within guide slotsprovided in stabilizer base 600. In a preferred embodiment, top member605 has side projections or rails 608 and 609 which snap into lowerslots or channels 611 and 610 in stabilizer base 600 as top member 605is urged into a concentric position over stabilizer base 600. Rails 608and 609 slide within channel 611 and 610 to maintain a secure attachmentand controlled rotation of top member 605 and stabilizer base 600. Topmember 605 may optionally have tab 612 adapted to be received withinupper slot 604 on stabilizer base 600. Upper slot 604 may have aplurality of detents or teeth which form a desired number of detentedpositions as tab 612 is rotated around the path of upper slot 604. In apreferred embodiment, detented position 617 is formed between tooth 613and slot end 616 and detented position 618 is formed between tooth 614and tooth 615. Of course, detented positions may be created at anydesired location using a variety of alternate constructions. Preferably,the detent action of tab 612 allows the operator to manually select aposition of ball/post 602, but then holds the position of top member 605relative to stabilizer base 600 against movement during use to ensureeffective stabilization of a target vessel on the beating heart.

In addition to the critical function of stabilizing the beating heart,it is also important for the tissue stabilizer to present the stabilizedcoronary artery in a manner which allows sutures to be easily placedaround the mouth of the arteriotomy as required to create theanastomosis. FIGS. 51A-54 illustrate a tissue stabilizer embodimentinvolving a base portion having a single contacting surface forstabilizing a target vessel on the beating heart and a mechanical bailelement to facilitate optimal vessel presentation.

Referring to FIGS. 51A and 51B stabilizer base 740 is shown attached toconnecting shaft 3 using ball/post 730. Connecting shaft 3 is shownconnected generally to the center of stabilizer base 740 atapproximately a right angle, however, as discussed above, the ball/post730 could be connected at any desired offset or orientation or theposition of ball/post 730 could be adjustable. Stabilizer base 740preferably has a single contacting surface 742 which may be flat orcurved to at least partially conform to the surface of the heart.Contacting surface 742 is sized to provide sufficient contacting areasuch that sufficient compressive force can be applied to the beatingheart to achieve effective immobilization or stabilization of a targetcoronary artery.

Stablizer base 740 preferably has an extending frame member or bail 745attached thereto. Bail 745 may be a thin, round or squarecross-sectioned member, and is preferably a stainless steel wire. Bail740 has a bail portion 756 which is generally parallel to stabilizerbase 740 and may have relieved sections 747 formed therein so as not toocclude the vessel during use. Bail portion 756 may have tissue grippingfeatures, such as teeth 755. In an optional embodiment, bail portion 756may be provided with rotating cover or a spiral wound thread (not shown)so that bail portion may be more easily repositioned, under astabilizing load, over the surface of the heart as discussed below.

In a preferred embodiment, bail 745 is moveable relative to stabilizerbase 740. Bail 745 can be moved in or out in the direction indicated byarrow 750 to cause bail section 756, which is generally parallel withstabilizer base 740, to compress tissue towards stabilizer base 740 orstretch tissue away from stabilizer base 740. Thus, bail 745 can bemoved in and out to compress or stretch the tissue surrounding acoronary artery until the optimum presentation for performing theanastomosis is achieved. The generally parallel portion may bevertically offset from contacting surface 742 by a distance 757 which istypically about 0.050 inches to about 0.200 inches.

Although bail 745 may be attached in a number of ways, bail 745 ispreferably formed with first and second end portions 748 and 749 havingdetents or teeth 746. Stabilizer base 740 preferably has channels 751and 752 for receiving end portions 749 and 748 respectively. Channels751 and 752 preferably have internal mating teeth 753 for engaging teeth746. End portions 748 and 749 can be incrementally advanced intochannels 752 and 751 as teeth 746 deflect and release from a matedposition relative to teeth 753 and then successively engage the nextmated position. Stabilizer base 740 may include cover 754 over channels751 and 752. So that the stabilizer can be removed from around acompleted anastomosis, at least one end of bail 745 is detachable fromstabilizer base 740. In a preferred embodiment, stabilizer base 740 issubstantially symmetrical allowing bail 745 to be assembled from eitherside in a right or left handed configuration.

Bail 745 is preferably flexible or semi-flexible relative to stabilizerbase 740. As a result of its inherent flexibility, bail 745 applies apredetermined force against the heart that, under operating conditions,may be generally independent of the stabilizing force applied tostabilizer base 740 to stabilize the beating heart. That is, oncestabilizer base 740 is forced against the surface of the heart, theforce applied by bail 745 is a function of its mechanical spring raterelative to stabilizer base 740.

FIGS. 52A and 52B illustrate another single contact stabilizer basehaving a bail 762 which is secured at only one end. Stabilizer base 760may have a housing 765 having a series of internal teeth (not shown).Bail 762 has a toothed end 766 which is received within housing 765 toengage with the mating teeth provided therein. As with the embodimentabove, bail 762 has a generally parallel portion 763 which is moveablerelative to stabilizer base 760 in the direction generally indicated byarrow 767 to stretch or compress the surrounding tissue for optimumvessel presentation. Bail 762 may have tab 761 to facilitate grasping byan instrument, such as for example forceps 761. The free end 764 of bail762 is preferably rounded or somewhat bulbous so as to be atraumatic.Because bail 762 attaches only at one end, the stabilizer can be easilyremoved from the completed anastomosis without removing bail 762 fromstabilizer base 760.

In another embodiment of the stabilizer, the wire frame member or bailmay have a drive mechanism for moving the bail relative to thestabilizer base. Referring to FIG. 53 stabilizer base 770 has housing771 which is constructed with guide channel 774 having gear 775 mountedfor rotation therein. Bail 772 has a toothed end 773 which may beassembled within guide channel 774 such that rotation of gear 775 causesbail 772 to be moved in and out in the direction indicated by arrow 43.Gear 775 may be driven by any suitable tool, for example, gear 775 mayhave a drive hole 778 for engagement by a suitable drive tool 771.

Another driven bail stabilizer is shown in FIG. 54. In this embodiment,stabilizer base 780 has threaded shaft 781 preferably supported at itsend portions by bushings or bearings 783 and 784. One end of thethreaded shaft is connected to a flexible drive 785 through a flexibleor universal joint 791. The flexible drive may be routed up connectingshaft 3. Preferably flexible drive 785 is secured to connecting shaft 3by way of a thin polymeric coating. Bail 782 is connected to threadedcollar 787 which cooperates with threaded shaft 781 to move bail in andout relative to stabilizer base 780 in the general direction indicatedby arrow 790. The screw and collar drive mechanism is preferablyconcealed by housing 788 which has only a small slotted opening 786allowing passage of bail 782.

With each of the flexible bail embodiments described above,stabilization and vessel presentation are relatively independent. First,the beating heart is typically stabilized using a compressive forcedelivered by way of the single contacting surface provided by thestabilizer base. The bail may then be manipulated in or out to obtainthe optimum presentation of the vessel for whatever surgical procedureis underway. For example, one bail position may be optimal for creatingthe arteriotomy, another bail position for insertion of a shunt or likedevice (should one be used), another bail position for creating theanastomosis, and so on. All the while, the stabilization of the beatingheart itself remains optimized by the contacting surface of thestabilizer base.

The Stabilization System

Preferred embodiments for each of the retractor, the instrument mountand the tissue stabilizers have been discussed in detail above. Whileeach component may be utilized separately, superior access andstabilization can be achieved when the multiple components are usedtogether for performing a minimally invasive cardiac surgery, preferablythrough a sternotomy approach. Referring to FIG. 55, retractor assembly900, including drive mechanism 910 and first and second platform blades915 and 920, may be used to spread the sternum, providing access anddirect visualization to the thoracic cavity. Retractor assembly 900 alsoallows sutures to be fixed or organized. Stabilizer assembly 800isolates and provides local immobilization of the target vessel on thebeating heart. Instrument mount assembly 850 facilitates precisemaneuvering of the stabilizer and ensures a stable, motion free mount atthe desired position and orientation.

To begin a typical beating heart CABG procedure using the preferredstabilization system illustrated in FIG. 55, drive mechanism 910 ispreferably placed in the fully closed position with moveable housing 925positioned against or adjacent fixed housing 930. First platform blade915 is then assembled to moveable housing 925 and a second platformblade 920 is assembled to fixed housing 930. After ensuring thatplatform blades 915 and 920 are fully and securely attached to drivemechanism 910, engaging members 935 of platform blades 915 and 920 aresecurely seated on the incised sternum created using standard surgicalprocedures. Drive handle 940 may then be rotated clockwise to separateplatform blades 915 and 920, thus creating the desired opening foraccessing the beating heart.

If positioning the heart using sutures to position the heart, thesutures may be placed through the tissue at the desired location andsecured to platform blades 915 and 920. Sutures 945 may be slid intosuture holder slots 950 to engage the suture. To ensure proper a properhold, only one suture strand is preferably engaged within each sutureholder slot 950. Sutures 945 are released from platform blades 915 and920 by concurrently pulling back and up on suture 945 while pulling thesuture through the suture holder slot 950.

With the heart positioned as desired, instrument mount assembly 850 maybe assembled to platform blade 920 (or 915) by hooking stabilizer mountbase 955 onto rail 960 (or 961) at the desired location and moving thebase lever (not visible in this view) clockwise to the closed positionto secure instrument mount assembly 850 onto rail 960. Mount body 110may be oriented to the desired angle by way of ball joint 965 and lockedinto place by turning the top mount knob 855 clockwise.

Stabilizer base 810, having contact members 812 and 814, may then bepositioned on the epicardium of the beating heart by gently loweringconnecting shaft 820 using one hand to guide stabilizer base 810 ontothe target area on the heart. Incremental pressure is applied tostabilizer base 810 situated on the epicardium until the desiredimmobilization or stabilization is achieved. Connecting shaft 820 issecured in the desired position by turning side mount knob 860 clockwiseand stabilizer base 810 is secured in the desired position relative toconnecting shaft 820 by turning the stabilizer shaft knob 830 clockwise.With the beating heart stabilized the anastomosis, or other desiredprocedure, is completed.

To remove stabilizer base 810, connecting shaft 820 is held with onehand while side mount knob 860is loosened with the other hand.Stabilizer base 810 is then carefully removed from the anastomotic site.The base lever is moved to the open position to release instrument mountassembly 850, and stabilizer assembly 800 mounted thereto, from rail 960on platform blade 920. When the entire bypass procedure is completed,drive handle 940 is rotated in the counter clockwise direction to closedrive mechaninsm 910 and platform blades 915 and 920. Retractor assembly900 may then be gently removed from the access incision. To removeplatform blades 915 and 920 from moveable housing 925 and fixed housing930, respectively, release latches 970 are manually activated andplatform blades 915 and 920 may be pulled generally straight away fromdrive mechanism 910. Drive mechanism 910 may then be sterilized andprepared for use in a subsequent procedure.

While certain embodiments are illustrated in the drawings and have justbeen described herein, it will be apparent to those skilled in the artthat many modifications can be made to the embodiments without departingfrom the inventive concepts described. For purposes of illustrationonly, the principles of the present invention has been generallydescribed with reference to a coronary artery bypass procedure, but mayreadily be applied to other types surgical procedures not specificallydescribed. Many other uses are well-known in the art, and the conceptsdescribed herein are equally applicable to those other uses. Further,the different components of the various exemplar embodiments describedabove can be combined in any desirable construction. Accordingly, theinvention is not to be restricted except by the claims which follow.

What is claimed is:
 1. A surgical retractor system for creating anopening through an incision in a patient comprising: a drive mechanismhaving attached thereto a first retractor blade and a second retractorblade, said first and second retractor blades being substantiallyparallel and adapted to engage opposite sides of said incision, saidfirst retractor blade being moveable relative to said second retractorblade; at least one of said first and second retractor blades having arail extending upwardly therefrom, said rail having at least one openslot for receiving one or more sutures therein.
 2. The surgicalretractor system of claim 1, wherein said rail has a top section adaptedto engage a separate mount.
 3. The surgical retractor system of claim 2,wherein said rail has a T-shaped cross-section.
 4. The surgicalretractor system of claim 3 wherein said at least one open slot istransverse to said rail, said at least one open slot having a depthwhich allows said one or more sutures to be positioned completely belowsaid top section.
 5. The surgical retractor system of claim 1 whereinsaid rail is curved along its length.
 6. The surgical retractor systemof claim 1 wherein said first retractor blade has a first rail and saidsecond retractor blade has a second rail, said first and second railsbeing curved along their respective lengths.
 7. The surgical retractorsystem of claim 1 wherein said at least one open slot has an internalwall and said surgical retractor system further comprises a suturelocking member, said suture locking member comprising a body having afixed end and a free end, said free end engaging said internal wall soas to clamp a suture placed between said free end and said internalwall.
 8. The surgical retractor system of claim 7 wherein said body isat an acute angle relative to said open slot.
 9. The surgical retractorsystem of claim 7 wherein said body is substantially rigid and pivotsabout said fixed end.
 10. The surgical retractor system of claim 7wherein said body is flexible.
 11. A surgical retractor for use inoperating on a heart, comprising: a drive mechanism having a firstretractor blade and a second retractor blade attached thereto in anopposing relationship for engaging opposite sides of an incision intothe thoracic cavity, said first retractor blade being moveable relativeto said second retractor blade to create a widened opening through saidincision; at least one of said first and second retractor blades havingan open slot for receiving a suture, said open slot having at least oneinternal wall; and a suture locking member, said suture locking membercomprising a body having a fixed end and a free end, said body beingpivotable about said fixed end so as to urge said free end against saidinternal wall.
 12. The surgical retractor of claim 11 wherein said bodyhas a central axis extending from said free end to said fixed end, saidcentral axis of said body being at an angle of less than 90 degrees withsaid open slot.
 13. The surgical retractor of claim 12 wherein saidangle is between about 65 degrees and about 90 degrees.
 14. The surgicalretractor of claim 12 wherein said free end has a plurality of ridgesformed therein.
 15. The surgical retractor of claim 11 wherein at leasta portion of said fixed end is substantially cylindrical.